摘要
西北太平洋海陆相互作用强烈,受黑潮和亚洲大陆风尘输入影响显著,是研究海洋沉积物中有机碳埋藏与陆源输入、海洋初级生产力和海洋环境演化关系的理想靶区。本研究基于采自九州-帕劳海脊北部的重力活塞647 cm长的KPR12岩芯,分析了总有机碳(TOC)、总氮(TN)、有机碳稳定碳同位素组成(δ^13CTOC)、蛋白石(Opal)以及粒度等指标,初步探讨了近40万年来轨道尺度沉积有机碳的来源、埋藏特征及其影响机制。岩芯的TOC含量平均值为0.214%,呈冰期较高、间冰期较低的旋回特征。岩芯沉积物粒度的不同端元反映了研究区风尘输入大致呈冰期较高的趋势。岩芯的δ^13CTOC(-25.24‰^-21.04‰,平均值为-22.59‰)显示有机质以海源为主(约62%),海源有机碳含量趋势与TOC的变化一致。研究区不同时期陆源物质的输入受风尘输送和黑潮的综合控制,黑潮增强可能对该区间冰期陆源有机碳贡献的升高有一定影响。岩芯中TOC与Opal含量的相关性分析表明,海洋初级生产力可能不是控制该岩芯有机碳含量变化的主要原因。冰期-间冰期旋回中的深层水通风条件、黑潮和北太平洋中层水的发育以及陆源细颗粒物质输入可能共同影响着本区沉积有机碳的降解与埋藏保存。
In the global carbon cycle,the burial of organic carbon(OC)in marine sediments in geological periods is closely related to terrestrial input,marine primary productivity and marine environment.There is a lack of long-term OC record in the Northwest Pacific(NWP)Ocean,where is an ideal target region for studying the source,burial and preservation of OC with its environmental implication in the glacial-interglacial cycles.In this study,based on the glacial-interglacial timescale,we present a record of sedimentary OC burial from northern Kyushu-Palau Ridge since Late Quaternary and preliminarily explain their controlling factors and the potential environmental implication.The gravity core KPR12(647 cm length)was collected from the northern Kyushu-Palau Ridge in the NWP(29°28'N,133°37'E;2590 m in depth)in 2016,where is affected by the Kuroshio Current,the dust input from Asian Continent and the volcanic eruption of Kyushu Island in Japan.We used AMS 14C dating,planktonic foraminiferal oxygen isotope records to establish the age model.We also analyzed the sediment grain size,opal,total organic carbon(TOC),total nitrogen(TN),stable carbon isotope of TOC(δ^13CTOC),and finally established the sediment record of OC burial in this area through the last 400 ka.The results showed that the mean TOC content is 0.214%,which is characterized by higher values during glacial periods compared to that in the interglacial time(OCGlacial=0.25%,OCInterglacial=0.18%).The meanδ^13CTOC value in this core is-22.59‰,indicating a mixed OM sources with the dominant contribution from marine origin(ca.62%).There existed a good correlation trend between TOC and marine-derived OC,suggesting that the variation of TOC record may co-varied with the changes of marine-derived OC;while the terrestrial OC is probably correlated to the Kuroshio Current and dust input.The variations of the end members of grain size can reflect the influence of Westerlies(F1:5.23μm,fine grain),East Asian Winter Wind(F2:19.87μm,medium-coarse grain)and volcanic material(F3:93.51μm,coarse grain)input,with a higher dust input during the glacial periods,which is consistent with the patterns of TOC records.According to the decoupled variation trends and few correlations between TOC and Opal(R2=0.04)in core KPR12,it means that marine primary productivity may not be the main factor to control the OC burial.Furthermore,the Kuroshio Current,North Pacific Intermediate Water(NPIW),Antarctic Bottom Water(AABW)and Circumpolor Deep Water(CDW)may together influence the change of dissolved oxygen in the bottom water column of NWP and promote the burial and preservation of the sedimentary OC in the study area.On the other hand,the increased input of fine particles from terrestrial sources during the glacial periods could also enhance the burial and preservation of OC through a quick transfer and deposition of particulate OM in the water column.In summary,the ventilation variation during the glacial-interglacial cycles,Kuroshio condition and development of the NPIW as well as the terrigenous fine-grained sediment input could work together to regulate the degradation and burial of sediment OC in this area.
作者
张钰莹
胡利民
吴永华
姚政权
董智
Minoru Ikehara
白亚之
王湘芹
范迪
石学法
Zhang Yuying;Hu Limin;Wu Yonghua;Yao Zhengquan;Dong Zhi;Minoru Ikehara;Bai Yazhi;Wang Xiangqin;Fan Di;Shi Xuefa(Key Laboratory of Marine Geology and Metallogeny,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,Shandong;Laboratory for Marine Geology,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,Shandong;Collaborative Innovation Center of South China Sea Studies,Nanjing University,Nanjing 210093,Jiangsu;Kochi University,Center for Advanced Marine Core Research,Kochi,Japan 783-8502;Center for Isotope Geochemistry and Geochronology,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,Shandong)
出处
《第四纪研究》
CAS
CSCD
北大核心
2020年第3期658-672,共15页
Quaternary Sciences
基金
国家重点基础研究发展计划项目(批准号:2016YFA0601903)
青岛海洋科学与技术试点国家实验室鳌山科技创新计划项目(批准号:2016ASKJ13)
中央级公益性科研院所基本科研业务费专项项目(批准号:2017S01)
国家自然科学基金项目(批准号:U1606401和41722603)
山东省"泰山学者"建设工程专项经费项目(批准号:TSQN20182117)共同资助。
关键词
有机碳埋藏
海洋初级生产力
风尘输入
黑潮
冰期-间冰期
西北太平洋
organic carbon burial
oceanic primary productivity
dust input
Kuroshio Current
glacial-interglacial
Northwest Pacific
